Fire-door of boiler-furnaces.



G. DE GRAHL.

FIRE DOOR OF BOILER FURNACES.

APPLICATION FILED 0011s, 1910.

1,051,220. Patented Jan. 21, 1913.

3 SHEETS-SHEET l.

- FIE. 1.

I j 2 31 13 3 41 14 i G. DE GRAHL.

FIRE DOOR OF BOILER FURNACES.

APPLICATION FILED 0013.13, 1910.

Patented Jan. 21, 1913.

3 SHEETSSEEET 2.

COLUMBIA PLANonnAPu cn., WASHINGTON, u. c.

G. DE GRAHL.

FIRE DOOR 0F BOILER FURNACES.

APPLICATION FILED 00T.l3, 1910.

Patented Jan. 21, 1913.

3 SHEETS-SHEET 3.

coLulBlA PLANMRAIH CO..wAsHlNn'roN. D. c.

UNITED STATES;

PATEN T OFFIQE.

FIRE-DOOR OF BOILER-FURNACES.

roenaeo.

Specification of Letters Patent.

Application filed October 13, 1910.

Patented Jan. 21, 1913.

Serial No. 586,862.

T0 at whom it may concern:

Be it known that I, GUSTAV on GRAl-IL, a

subject of the German Emperor, and residing at Zehlendorf, near Berlin, Germany, have invented certain new and useful Improvements in Fire-Doors of Boiler-Furnaces, of which the following is a specification. a

My invention relates to devices for preventing the formation of smoke in furnaces, operated with artificial draft, in which the fire-box is connected by way of one or more air-conduits with the atmosphere.

A primary object of my invention is to provide a device of this type comprising bot-h one or more air-conduits in the horizontally-opening fire-do0r and at least one steam nozzle, serving for producing a steam film, opening above the door into the firebox in such a manner that the supplementary air entering through the one or more air-conduits into the fire-box is controlled by the steam issuing from the steam nozzle.

I may arrange the steam nozzles perpen- .dicularly above the lines passing through the centers of the air-conduits. The steam issuing from the nozzles tends to draw supplementary air through the air-conduits and to cause this air entering into the fire-box to mix intimately with the unconsumed gases. If steam nozzles were arranged perpendicularly above air-conduits in the doorframe, the steam issuing from the steam nozzles would not draw air through the air conduits, because air-conduits in the doorframe can only be so arranged that they open not directly into the fire-box, but opposite one another in the space surrounded by the door-frame In contradistinction to this arrangement, by varying the strength of the steam film obtained according to my invention I can regulate the quantity of supplementary air entering into the fire-box.

Another advantage of my device is that after the fire-door has been opened the airconduits can be cleaned, even while the furnace is working, that is can be freed from ash and cinder deposited in the same. Moreover, any air-valves in the air-conduits, opening automatically in consequence of the partial vacuum in the fire-box, can easily be repaired or exchanged without disturbing the working of the furnace, this being possible,-when air-conduits are provided in the door-frame, usually only after the latter has been dismounted. Allso, considerable saving of space is effected by arranging the air-conduits in the fire-door instead of in the door-frame.

One illustrative embodiment of my inven tion and a modification thereof are represented by way of example in the accompanying drawings, wherein Figures 1 to at illustrate one form of my apparatus and Figs.

to 7 a modification thereof.

In said drawings Figs. 1 and 2 are vertical section and front elevation, respectively; Fig. 3 is a horizontal section through the fire-door taken on the line AB in Fi 2, and Fig. 4 is a vertical section through the fire-door taken on the line CD in Fig. 2; Fig. 5 is a front elevation, Fig. 6 a horizontal section through the fire-door taken on the line E-F in Fig. 5, and Fig. 7 a vertical section through the fire-door taken on the line G-l-I in Fig. 5.

Referring firstly to Figs. 1 to the numeral 1 designates the firebox having the opening 3, bordered by the ring 2, through which the fuel is introduced. The plate 4: carrying the bearing 5 for the perpendicw lar door-shaft 6 is secured on the outer wall of the fire-box. The two hinge-straps T. 8 of the door are fast on the shaft 6, to. which the forked head 12 of the handle 11 is firmly secured. The rotary motion of the door with the shaft 6 is also assured by the bushing 9, fast on the shaft, engaging by means of a projection 10 in a corresponding to oess in the hinge-strap 7. The door 13 has an inner wall l-fl extending not only halfway up the same but laterally only to the transverse walls 15, 16 (Figs. 1 and The two air-conduits 19, 20 are bordered both by these llll'lSVQISG walls and by the lateral. walls 17, 18 of the door. The door 13 is provided with the battle-plate 41, secured to it, the breadth of which is somewhat larger than the distance between the two transverse-walls 15, 16. These conduits possess ribs 21, 22 for warming the supplementary air entering into the fire-box through the same. Non-return valves 23, 24 formed as flap-valves, each having a pivot 25, are provided in the air-conduits. The flaps have such dimensions that they open even with a slight draft, for example one produced by an auxiliary blower, so that a cataract hav ing a piston acting on the valves can be dispensed with. Steam nozzles 26, 27 openmg into the fire-box and serving for forming a steam film are provided above the door opening, the line passing through the center of each steam nozzle being located approximately in the vertical central plane of the corresponding air-conduit. The steam film formed by the steam issuing from the nozzle 26 is indicated by the line 31 in Fig. 1. The nozzles are connected by branch pipes 28, 29 with the steam pipe 30 in which the stop-valve 32 is interposed. In proportion as the draft in the fire-box increases, the valves 23, 2 L are lifted more or less, so that supplementary air entering through the airconduits 19, 20, is preliminarily warmed therein by the hot ribs 21, 22 and passes in the firebox under the steam film which compels it to enter into intimate contact with the still unconsumed gases, thereby favoring the combustion of carbon monoxid to carbon dioxid, of hydrogen to water, of methane ((3H,) to carbon dioxid (CO and water (H 0), and so on. According as the valve 32 is opened more or less, not only is the strength of the steam films varied but also the quantity of air drawn through the air-conduits into the fire-box by the steam issuing from the steam nozzles is controlled.

Referring now to Figs. 5 to 7, the apparatus here shown differs from the form just described merely by the fire-door 13 being provided with only a single air-conduit 39 situated in the middle part of the door, bordered laterally by the walls 34, 35, provided with ribs 36 for preliminarily warming the supplementary air, and containing the non-return fiapvalve 37 mounted revolubly on a pivot 38. The door 13 is provided with the battleplates 42, which extend but a little over the walls of the airconduit 39, so that the air passing the airconduit is not prevented from entering the fire-box by the bathe-plates. The nozzle 40, connected with the steam pipe 30, for producing the steam film, opens above the fire-door into the firebox. ,The line passing through the center of the nozzle 40 is located substantially in the vertical central plane of the air-conduit 39.

The mode of operation of this modified form is similar to that of the device first described. In this case also the supplementary air, preliminarily warmed by the ribs 36 while passing through the air-conduit 39, will pass through the fire-box below the steam film, so that the supplementary air is intimately mixed with the flue gases.

I claim 1. In a furnace of the character described the combination with the fire-box, having a fire-door-opening, of a horizontally opening fire-door, having one or more air-conduits somewhat inclined to the vertical, and limited by walls, having an unchangeable position with regard to the fire-door, one or more steam-nozzles, situated above said airconduits, and connected with a steam-pipe being provided with a closure member for controlling the steam-admission to the said steam-nozzles, said air-conduits being provided with ribs, for heating the air vpassing through the air-conduits, and connected below with the external air and opening above parallel to the side-walls into the fire-box, and cooperating with said steamnozzles, said air-conduits being provided with non-returnvalves adapted to be opened automatically under the influence of the draft in the fire-box. I

2, In a furnace of the character described the combination with the fire-box, having a fire-door-opening, of a horizontally opening fire=door, having one or more air-conduits, somewhat inclined to the vertical and limited by walls, having an unchangeable position with regard'to the fire-door, one or more steam-nozzles situated above said airconduits and connected with a steam-pipe being provided with a closure member for controlling the steam-admission to the'said steam-nozzles, said air-conduits, being provided with ribs, forheatingthe airpassing through the air-conduits and connected below with the external air and opening above parallel to the side-walls into the fire-box, and cooperating with said steam-nozzles, said air-conduits being providedwith nonreturn-valves, adapted to be opened auto- -matically under the influence of the draft in the fire-box, to said door a baflie-plate is secured as far as the door is not occupied by the air-conduit. I r

In testimony whereof, I afiix my signature in the presence of two witnesses.

GUSTAV DE GRAHL. lVitnesses HENRY Hnsrnn, IVOLDEMAR HAUPT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of 'Patents, Washington, D. C 

